February 25
Week Three
This the assignment was to learn electronics fabrication by making a FabIsp. FabIsp is an In system programmer for AVR microcontrollers. The PCB was already designed and given that I have some experince with electronics I was looking forward to an easy time. On the contrary I did not manage to mill the board and had to look for alternative means of creating the board. The modella in the lab has not been working for sometime now. I decided to use the vinyl cutter but without much success as shown in th picture below. On hitting this dead end I decided to etch the board.
To start with I downloaded the eagle files for the fabisp and opened the board file with eagle. Then I printed(mirrored) on a glossy paper ready for toner transfer using a hot iron. After the toner transfer. I soaked the board in warm water with a little bicarbonate of Soda to soften the paper for removal.
After removing the paper and cleaning the board I etched away the unwanted copper using a a ferric chloride bath. When the board was done I soldered the parts on but missed a 1k resistor and I had to use a through hole one mounted on the pads. On connecting the fabisp to the my computer it was not recognised.
I then closed SJ1 Jumper and used an AVRISPMKII and AtmelStudio 6 to upload firmware to my board. On connecting to the computer the programmer was recognised as FabIsp but it indicated that there was a problem. After Installing the usbtiny drivers the programmer was recognised.
When the programmer was recognised I decided to try reading the signature of ATMEGA328 on an arduino board and see if it will work. This failed several times and I wondered what had gone wrong. This is what I was getting.
Finaly I realised that I was connecting the isp cable the wrong way and on reversing! VOILA.. IT WORKED.
I went ahead and burnt boot loader on new atmega328p chips and proved that the programmer actually works.
